Encabezado: Un grupo de investigadores desea saber si existe una diferencia significativa en la altura media de dos especies de plantas que habitan una misma región. Para ello, seleccionaron aleatoriamente muestras de ambas especies y midieron su altura (en centímetros). Los datos de las alturas de las plantas son los siguientes: Especie A (n = 10): 55, 60, 58, \( 54,57,62,59,56 \), 61,60 ¿Cuál es la media de la altura de las * 1 punto plantas de la Especie A? 60.1 58.2 56.5

9 A \( 99 \% \) confidence interval for the mean mass of steel sheets produced in a factory is \( (30.37 \mathrm{~kg}, 32.43 \mathrm{~kg}) \). This interval is based on a random sample of 36 steel sheets. Find a \( 95 \% \) confidence interval for the mean mass of steel sheets, assuming that the masses of steel sheets are normally distributed.

The first step involved in calculating the Pearson correlation coefficient is to sum all the scores square all the scores calculate the standard deviation for each variable

Coffee consumption has been found to be negatively correlated with amount of sleep, with a correlation coefficient of 0.5 . How much can the coffee consumption account for the variance of amount of sleep? \( 0.5 \% \) \( 50 \% \) \( 0.25 \% \) \( 25 \% \)

Many investors and financial analysts believe the Dow Jones Industrial Average (DJIA) gives a good barometer of the overall stock market. On January 31, 2006, 9 of the 30 stocks making up the DJIA increased in price (The Wall Street Journal, February 1, 2006). On the basis of this fact, a financial analyst claims we can assume that \( 30 \% \) of the stocks traded on the New York Stock Exchange (NYSE) went up the same day. A sample of 76 stocks traded on the NYSE that day showed that 10 went up. You are conducting a study to see if the proportion of stocks that went up is is significantly less than 0.3 . You use a significance level of \( \alpha=0.002 \). What is the test statistic for this sample? Use \( \hat{p} \) rounded to 4 decimal places. (Report answer accurate to 4 decimal places.) test statistic \( =-3.198^{\circ} \times \)

Which of these values of the correlation coefficient indicates the weakest relationship between two variables? -0.30 -0.18 0.03 0.42